The size classes aren't hugely consistent even with the Hasbro figures.

Best way to see if you like the reissues is to get one of the Autobot cars. They're probably a bit smaller than you're expecting, although you have the advantage of not having grown up with them and remembering differently.

G1 just marked em by subgroup, or in the occasion of a singular or rare rank/function, such as "City Commander" or "Communicator". They didn't have clearly delineated "scout/deluxe/voyager" classes, although you could probably go through the line nowadays and sort them to some degree or another.